Nested lists should be inside a <li> element of the list in which it is nested. At the moment, embedded <ol> tags appear at the same level as the <li> tags instead of inside.
HTML5 W3C ol spec: HTML5 ol. Note that an <ol> element may contain exactly zero or more <li> elements.
- Create a new page or label in Moodle
- Click the Atto editor toolbar button to create a numbered (ordered) list.
- Type a few lines of content. A single word will do.
- Press the Indent button in the Atto toolbar.
- Type a few more lines of content.
- Switch to the HTML view.
Instead of valid HTML similar to this:
Atto is producing this invalid HTML:
What is even worse is that, if you try to fix it, Atto just goes and re-arranges it all back to the way it was.
This creates an accessibility failure of WCAG 2.1, specifically criterion 4.1.1 Parsing.